水杨酸对湖北海棠活性氧代谢及超微弱发光的影响

 以50 μg·mL ^{- 1}水杨酸( SA) 喷施湖北海棠(Malus hupehensis Rehd. ) 幼苗, 结果显示: 超氧阴离子O^·₂ 的产生速率在处理后12～48 h明显高于对照, 而在72 h以后明显低于对照; H₂O₂ 含量在水杨酸处理后, 始终高于对照, 并在处理后第12和48小时出现两次峰值。POD活性在处理12 h后逐渐增加,SOD活性则在处理48 h后才有显著的增加, 而CAT在处理后24 h内活性高于对照, 48 h后明显低于对照。SA还明显促进了脂过氧化产物丙二醛(MDA) 的产生, 也明显促进了叶片的超微弱发光, 超微弱发光值在处理后的120 h内始终高于对照, 但在整个试验过程中超微弱发光的变化趋势与H₂O₂ 含量及O^·₂ 的产生速率的变化趋势明显不同。     

The N-acetyltransferase gene-implicated iron acquisition contributes to host specificity of Pseudomonas cichorii strain SPC9018 and its virulence

A pathogenicity island within the genome of a multi-host plant bacterium, Pseudomonas cichorii strain SPC9018, comprises the hrp genes encoding a type III secretion system and the pat gene encoding an N-acetyltransferase proposed to play a role in virulence. However, the function of the N-acetyltransferase remains poorly characterized. Interestingly, limiting the iron condition using a phytosiderophore, mugineic acid, resulted in reduced virulence of strain SPC9018 on respective host plants, including eggplant, similar to the reduced virulence observed with a pat gene-deletion mutant. Spectroscopic analyses showed that the pat deletion reduced the concentration of pyoverdine, which is the main siderophore produced by strain SPC9018, leading to a reduction in pyoverdine-mediated iron acquisition. Furthermore, the pat gene deletion mutant showed enhanced expression of the fecA, pvdL, and pvdR genes, whose expression is induced under deficient siderophore-mediated iron uptake. The pat-deletion mutant showed a hyper-swarming phenotype, and the addition of iron decreased this swarming motility. The pat deletion also reduced the adhesion ability of the bacteria, similar to the effect of iron-limited conditions. Furthermore, deletion of the pat gene enhanced expression of the hrp genes. These findings suggested that the pat gene encoding the N-acetyltransferase may be implicated in iron acquisition, contributing to host specificity of P. cichorii strain SPC9018 and its virulence.     

Effects of Compound Plant Nutrients on Rumen Fermentation Parameters,Rumen Microbiota and Fatty Acid Composition of Longissimus dorsi Muscle in Finishing Small Tail Han Sheep北大核心CSCD

This study was conducted to investigate the effects of compound p1ant nutrients (CPN) on rumen fermentation parameters, rumen microbiota and fatty acid composition of longissimus dorsi musc1e in finishing sma11 tai1 Han sheep. Sixteen 4-month-o1d finishing sma11 tai1 Han sheep with an initia1 body weight (BW) of (24.18±0.31) kg were random1y divided into two groups, name1y, with 8 rep1icates per group and 1 sheep per rep1icate. The sheep in the contro1 group were fed a basa1 diet, whereas the sheep of the contro1 group (CPN group) was fed the basa1 diet supp1ementation with 3‰ CPN. The experiment 1asted for 97 days after 7 days adaption. The resu1ts showed as fo11ows: compared with the contro1 group, 1) adding CPN decreased the concentration of ammonia nitrogen (NH3-N) (P<0.05); 2) CPN supp1ementation affected beta diversity of rumen microbiota; 3) the re1ative abundance of Acidobacteriota, Erysipe1otrichaceae_UCG-002, Lactobacillus, and Megasphaera were enhanced by adding CPN (P<0.05), whereas, the re1ative abundance of Bacteroidetes and Prevotella was 1ower (P<0.05); 4) the supp1ementation of CPN had no significant effect on fatty acid composition of longissimus dorsi musc1e of fattening sma11-tai1ed Han sheep (P>0.05); 5) the contents of tota1 MUFA, C18:1n9c, C14:1, C16:1, C18:2n6c, C18:3n3 and n-3PUFA in the longissimus dorsi musc1e were corre1ated with the re1ative abundance of Megasphaera, Erysipe1otrichaceae_UCG-002, Succiniclasticum and Ruminococcus (P<0.05). In conc1usion, CPN can regu1ate the rumen microbiota structure and reduce the rumen NH3-N concentration of fattening sma11-tai1ed Han sheep. In production practice, CPN can be used as a rumen eco1ogica1 regu1ator. © 2023 Authors. All rights reserved.     

CmRT1, a Ty3-gypsy-like retrotransposon in Castanea mollissima,is associated with a short-catkin mutation

Summary

Retrotransposons are major components of the genomes of most eukaryotic organisms and have resulted in the introduction of desirable traits in many crops, including fruit trees. Here, we describe a Ty3-gypsy-like retrotransposon associated with a short-catkin mutant in Chinese chestnut (Castanea mollissima), resulting in catkins that are < 20% the length of normal staminate catkins. A partial sequence of the retrotransposon, named CmRT1, detected by amplified fragment length polymorphism (AFLP) analysis, and its complete sequence were determined from the genome of Chinese chestnut (Castanea mollissima) using improved Tail-PCR. CmRT1 was 10,067 bp in length and shared high homology in its predicted amino acid sequence and motifs with other Ty3/gypsy-like retrotransposons. The 5’ long terminal repeat (LTR) of CmRT1 contained a TATA box and several cis-elements that were predicted to be important for processes involving abscisic acid, gibberellic acid, and auxins and in stress-mediated responses. Further characterisation of the transposition event that led to the short-catkin phenotype was performed using two pairs of primers that aligned with the flanking region of the LTRs. The expected PCR bands were observed only in genomic DNA from plants that showed the mutation. Finally, cloning and real-time qPCR analysis of an NADP-dependent alkenal double-bond reductase (CmADBR) target gene that was adjacent to CmRT1, revealed that CmADBR expression was significantly down-regulated in the short-catkin mutant. Taken together, these results suggest that the CmRT1 retrotransposon is responsible for the short-catkin phenotype.     

玉米粉和乳酸菌对甘薯蔓、酒糟及稻草混合青贮品质的影响

为评价玉米粉和乳酸菌对甘薯蔓、酒糟及稻草(4∶4∶2)混合青贮品质的影响,试验设对照组(CK)、玉米粉添加组(CF)、乳酸菌添加组(LAB)、玉米粉和乳酸菌组合添加组(CF+LAB),每个处理6个重复,室温下贮藏60 d开封,取样分析青贮品质。结果表明,添加玉米粉和乳酸菌制剂均明显提高了青贮料的感官品质,与CK相比,CF处理、LAB处理及CF+LAB处理中 CP含量极显著提高(P<0.01), NH₃-N/TN、AA、PA、Ash含量极显著降低(P<0.01),CF处理极显著地提高了DM、CP、LA含量(P<0.01),而LAB处理则极显著地降低了NDF、ADF含量(P<0.01),CF+LAB中NH₃-N/TN、AA含量及pH值极显著低于LAB(P<0.01),显著低于CF(P<0.05)。综上所述,添加玉米粉和乳酸菌制剂均提高了青贮品质,单独添加乳酸菌制剂青贮品质要次于单独添加玉米粉,两者组合添加青贮品质更好。     

添加丙酸和乳酸菌对杂交狼尾草青贮发酵品质的影响

研究丙酸、乳酸菌和两者组合不同添加水平对杂交狼尾草（Pennisetum americanum×P.purpereum）青贮发酵品质的影响。试验设对照(无添加)、乳酸菌(LAB)、0.2%丙酸、0.3%丙酸、0.4%丙酸、0.5%丙酸、0.2%丙酸+乳酸菌、0.3%丙酸+乳酸菌、0.4%丙酸+乳酸菌、0.5%丙酸+乳酸菌（占鲜质量比例）处理,青贮45 d后开袋分析。结果表明,添加丙酸可以有效改善杂交狼尾草的青贮品质,最佳添加量为0.3%;添加乳酸菌有助于提高杂交狼尾草的有氧稳定性。     

Transgene expression for Gladiolus plants grown outdoors and in the greenhouse

Transgene expression was evaluated for Gladiolus plants transformed with either the CaMV 35S, double CaMV 35S, rolD, or Arabidopsis UBQ3 promoter controlling the uidA or bean yellow mosaic virus coat protein gene in either the sense or antisense orientation to determine differences in expression for plants grown in the greenhouse and outdoors for two years. There was more variability in GUS expression when plants were grown outdoors than in the greenhouse for two years. Four of the six transformed plant lines with the UBQ3, rolD, and CaMV 35S promoters grown outdoors showed significant differences in GUS expression from year to year as compared to two of the six lines with the UBQ3 and rolD promoters grown in the greenhouse. When grown the same year, two plant lines with the CaMV 35S and one line with the rolD promoter showed 2–16× higher levels of GUS expression outdoors than in the greenhouse, and one plant line with the UBQ3 promoter had 31× higher GUS expression in the greenhouse instead of outdoors. Three of six plant lines transformed with the bean yellow mosaic virus coat protein gene in either the sense or antisense orientation under control of the double CaMV 35S promoter showed obvious transgene expression as compared to three lines that did not show expression or negligible expression for both years when plants were grown both outdoors and in the greenhouse. This study verified long-term gene expression, rather than silencing, for Gladiolus plants when grown outdoors and in the greenhouse from year to year.     

添加单宁酸对青贮葛藤茎叶品质的影响

为探讨添加单宁酸对青贮葛藤(Pueraria lobata (Willd.) Ohwi)茎叶品质的影响,以青绿葛藤茎叶为原料,添加3%和4%单宁酸青贮60 d后,对其进行感官鉴定,并进行有机酸、干物质损失率及营养成分的分析。结果表明:添加单宁酸的贮葛藤茎叶质地松散完整,具有酸香味,干物质损失率显著降低(P<0.05);可溶性碳水化合物和中性洗涤纤维含量显著增加(P<0.05);在添加单宁酸的青贮葛藤茎叶中,未检测出丙酸和丁酸。因此,葛藤青贮时添加单宁酸有利于营养物质的保持,可明显提高其品质。     

利用体外培养法建立饲料营养成分与瘤胃丙酸产量的回归模型

根据美国康乃尔净碳水化合物和蛋白质体系 (CNCPS) ,分析测定了 4类 2 4种饲料的营养成分 ,利用体外批次培养技术测定了它们在体外培养一定时间后的丙酸产量 ,并由此建立了饲料中产丙酸的营养成分和瘤胃丙酸产量的回归方程